High performance selective light wavelength filtering providing improved contrast sensitivity

ABSTRACT

The present invention relates to ophthalmic systems and coatings comprising a selective light wavelength filter, wherein said selective filter provides improved contrast sensitivity.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.15/813,017, filed Nov. 14, 2017, which is a continuation of U.S.application Ser. No. 15/048,625, filed Feb. 19, 2016, which is acontinuation of U.S. application Ser. No. 14/584,673, filed Dec. 29,2014, which is a continuation of U.S. application Ser. No. 13/233,768,filed Sep. 15, 2011, which is a divisional of U.S. application Ser. No.11/933,069, filed Oct. 31, 2007, which is a continuation-in-part of U.S.patent application Ser. No. 11/761,892, filed Jun. 12, 2007, which is acontinuation-in-part of U.S. patent application Ser. No. 11/378,317,filed Mar. 20, 2006 and which claims benefit of U.S. ProvisionalApplication 60/812,628, filed Jun. 12, 2006. U.S. application Ser. No.11/933,069 is also a continuation-in-part of U.S. patent applicationSer. No. 11/892,460, filed Aug. 23, 2007, which claims benefit of U.S.Provisional Application 60/839,432, filed Aug. 23, 2006; U.S.Provisional Application 60/841,502, filed Sep. 1, 2006; and U.S.Provisional Application 60/861,247, filed Nov. 28, 2006. U.S.application Ser. No. 11/933,069 also claims benefit of U.S. ProvisionalApplication 60/978,175, filed Oct. 8, 2007. All of these applicationsare incorporated by reference in their entireties.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to ophthalmic systems comprising aselective light wavelength filter, wherein said selective filterprovides improved contrast sensitivity.

2. Description of the Background

Electromagnetic radiation from the sun continuously bombards the Earth'satmosphere. Light is made up of electromagnetic radiation that travelsin waves. The electromagnetic spectrum includes radio waves, millimeterwaves, microwaves, infrared, visible light, ultra-violet (UVA and UVB),x-rays, and gamma rays. The visible light spectrum includes the longestvisible light wavelength of approximately 700 nm and the shortest ofapproximately 400 nm (nanometers or 10⁻⁹ meters). Blue light wavelengthsfall in the approximate range of 400 nm to 500 nm. For the ultra-violetbands, UVB wavelengths are from 290 nm to 320 nm, and UVA wavelengthsare from 320 nm to 400 nm. Gamma and x-rays make up the higherfrequencies of this spectrum and are absorbed by the atmosphere. Thewavelength spectrum of ultraviolet radiation (UVR) is 100-400 nm. MostUVR wavelengths are absorbed by the atmosphere, except where there areareas of stratospheric ozone depletion. Over the last 20 years, therehas been documented depletion of the ozone layer primarily due toindustrial pollution. Increased exposure to UVR has broad public healthimplications as an increased burden of UVR ocular and skin disease is tobe expected.

The ozone layer absorbs wavelengths up to 286 nm, thus shielding livingbeings from exposure to radiation with the highest energy. However, weare exposed to wavelengths above 286 nm, most of which falls within thehuman visual spectrum (400-700 nm). The human retina responds only tothe visible light portion of the electromagnetic spectrum. The shorterwavelengths pose the greatest hazard because they inversely contain moreenergy. Blue light has been shown to be the portion of the visiblespectrum that produces the most photochemical damage to animal retinalpigment epithelium (RPE) cells. Exposure to these wavelengths has beencalled the blue light hazard because these wavelengths are perceived asblue by the human eye.

Cataracts and macular degeneration are widely thought to result fromphotochemical damage to the intraocular lens and retina, respectively.Blue light exposure has also been shown to accelerate proliferation ofuvea melanoma cells. The most energetic photons in the visible spectrumhave wavelengths between 380 and 500 nm and are perceived as violet orblue. The wavelength dependence of photo toxicity summed over allmechanisms is often represented as an action spectrum, such as isdescribed in Mainster and Sparrow, “How Much Blue Light Should an IOLTransmit?” Br. J. Ophthalmol., 2003, v. 87, pp. 1523-29 and FIG. 6. Ineyes without an intraocular lens (aphakic eyes), light with wavelengthsshorter than 400 nm can cause damage. In phakic eyes, this light isabsorbed by the intraocular lens and therefore does not contribute toretinal photo toxicity; however it can cause optical degradation of thelens or cataracts.

The pupil of the eye responds to the photopic retinal illuminance, introlands, which is the product of the incident flux with thewavelength-dependent sensitivity of the retina and the projected area ofthe pupil. This sensitivity is described in Wyszecki and Stiles, ColorScience: Concepts and Methods, Quantitative Data and Formulae (Wiley:New York) 1982, esp. pages 102-107.

Current research strongly supports the premise that short wavelengthvisible light (blue light) having a wavelength of approximately 400nm-500 nm could be a contributing cause of AMD (age related maculardegeneration). It is believed that the highest level of blue lightabsorption occurs in a region around 430 nm, such as 400 nm-460 nm.Research further suggests that blue light worsens other causativefactors in AMD, such as heredity, tobacco smoke, and excessive alcoholconsumption.

The human retina includes multiple layers. These layers listed in orderfrom the first exposed to any light entering the eye to the deepestinclude the following:

1) Nerve Fiber Layer 2) Ganglion Cells 3) Inner Plexiform Layer 4)Bipolar and Horizontal Cells 5) Outer Plexiform Layer 6) Photoreceptors(Rods and Cones) 7) Retinal Pigment Epithelium (RPE) 8) Bruch's Membrane9) Choroid

When light is absorbed by the eye's photoreceptor cells, (rods andcones) the cells bleach and become unreceptive until they recover. Thisrecovery process is a metabolic process and is called the “visualcycle.” Absorption of blue light has been shown to reverse this processprematurely. This premature reversal increases the risk of oxidativedamage and is believed to lead to the buildup of the pigment lipofuscinin the retina. This build up occurs in the retinal pigment epithelium(RPE) layer. It is believed that aggregates of extra-cellular materialscalled drusen are formed due to the excessive amounts of lipofuscin.

Current research indicates that over the course of one's life, beginningwith that of an infant, metabolic waste byproducts accumulate within thepigment epithelium layer of the retina, due to light interactions withthe retina. This metabolic waste product is characterized by certainfluorophores, one of the most prominent being lipofuscin constituentA2E. In vitro studies by Sparrow indicate that lipofuscin chromophoreA2E found within the RPE is maximally excited by 430 nm light. It istheorized that a tipping point is reached when a combination of abuild-up of this metabolic waste (specifically the lipofuscinfluorophore) has achieved a certain level of accumulation, the humanbody's physiological ability to metabolize within the retina certain ofthis waste has diminished as one reaches a certain age threshold, and ablue light stimulus of the proper wavelength causes drusen to be formedin the RPE layer. It is believed that the drusen then further interfereswith the normal physiology/metabolic activity which allows for theproper nutrients to get to the photoreceptors thus contributing toage-related macular degeneration (AMD). AMD is the leading cause ofirreversible severe visual acuity loss in the United States and WesternWorld. The burden of AMD is expected to increase dramatically in thenext 20 years because of the projected shift in population and theoverall increase in the number of ageing individuals.

Drusen hinders or block the RPE layer from providing the propernutrients to the photoreceptors, which leads to damage or even death ofthese cells. To further complicate this process, it appears that whenlipofuscin absorbs blue light in high quantities it becomes toxic,causing further damage and/or death of the RPE cells. It is believedthat the lipofuscin constituent A2E is at least partly responsible forthe short-wavelength sensitivity of RPE cells. A2E has been shown to bemaximally excited by blue light; the photochemical events resulting fromsuch excitation can lead to cell death. See, for example, Janet R.Sparrow et al., “Blue light-absorbing intraocular lens and retinalpigment epithelium protection in vitro,” J. Cataract Refract. Surg.2004, vol. 30, pp. 873-78.

From a theoretical perspective, the following appears to take place:

1) Waste buildup occurs within the pigment epithelial level startingfrom infancy through out life.

2) Retinal metabolic activity and ability to deal with this wastetypically diminish with age.

3) The macula pigment typically decreases as one ages, thus filteringout less blue light.

4) Blue light causes the lipofuscin to become toxic. The resultingtoxicity damages pigment epithelial cells.

The lighting and vision care industries have standards as to humanvision exposure to UVA and UVB radiation. Surprisingly, no such standardis in place with regard to blue light. For example, in the commonfluorescent tubes available today, the glass envelope mostly blocksultra-violet light but blue light is transmitted with littleattenuation. In some cases, the envelope is designed to have enhancedtransmission in the blue region of the spectrum. Such artificial sourcesof light hazard may also cause eye damage.

Laboratory evidence by Sparrow at Columbia University has shown that ifabout 50% of the blue light within the wavelength range of 430+/−30 nmis blocked, RPE cell death caused by the blue light may be reduced by upto 80%. External eyewear such as sunglasses, spectacles, goggles, andcontact lenses that block blue light in an attempt to improve eye healthare disclosed, for example, in U.S. Pat. No. 6,955,430 to Pratt. Otherophthalmic devices whose object is to protect the retina from thisphototoxic light include intraocular and contact lenses. Theseophthalmic devices are positioned in the optical path betweenenvironmental light and the retina and generally contain or are coatedwith dyes that selectively absorb blue and violet light.

Other lenses are known that attempt to decrease chromatic aberration byblocking blue light. Chromatic aberration is caused by opticaldispersion of ocular media including the cornea, intraocular lens,aqueous humour, and vitreous humour. This dispersion focuses blue lightat a different image plane than light at longer wavelengths, leading todefocus of the full color image. Conventional blue blocking lenses aredescribed in U.S. Pat. No. 6,158,862 to Patel et al., U.S. Pat. No.5,662,707 to Jinkerson, U.S. Pat. No. 5,400,175 to Johansen, and U.S.Pat. No. 4,878,748 to Johansen.

Conventional methods for reducing blue light exposure of ocular mediatypically completely occlude light below a threshold wavelength, whilealso reducing light exposure at longer wavelengths. For example, thelenses described in U.S. Pat. No. 6,955,430 to Pratt transmit less than40% of the incident light at wavelengths as long as 650 nm, as shown inFIG. 6 of Pratt '430. The blue-light blocking lens disclosed by Johansenand Diffendaffer in U.S. Pat. No. 5,400,175 similarly attenuates lightby more than 60% throughout the visible spectrum, as illustrated in FIG.3 of the '175 patent.

Balancing the range and amount of blocked blue light may be difficult,as blocking and/or inhibiting blue light affects color balance, colorvision if one looks through the optical device, and the color in whichthe optical device is perceived. For example, shooting glasses appearbright yellow and block blue light. The shooting glasses often causecertain colors to become more apparent when one is looking into a bluesky, allowing for the shooter to see the object being targeted soonerand more accurately. While this works well for shooting glasses, itwould be unacceptable for many ophthalmic applications. In particular,such ophthalmic systems may be cosmetically unappealing because of ayellow or amber tint that is produced in lenses by blue blocking. Morespecifically, one common technique for blue blocking involves tinting ordyeing lenses with a blue blocking tint, such as BPI Filter Vision 450or BPI Diamond Dye 500. The tinting may be accomplished, for example, byimmersing the lens in a heated tint pot containing a blue blocking dyesolution for some predetermined period of time. Typically, the dyesolution has a yellow or amber color and thus imparts a yellow or ambertint to the lens. To many people, the appearance of this yellow or ambertint may be undesirable cosmetically. Moreover, the tint may interferewith the normal color perception of a lens user, making it difficult,for example, to correctly perceive the color of a traffic light or sign.

Efforts have been made to compensate for the yellowing effect ofconventional blue blocking filters. For example, blue blocking lenseshave been treated with additional dyes, such as blue, red or green dyes,to offset the yellowing effect. The treatment causes the additional dyesto become intermixed with the original blue blocking dyes. However,while this technique may reduce yellow in a blue blocked lens,intermixing of the dyes may reduce the effectiveness of the blueblocking by allowing more of the blue light spectrum through. Moreover,these conventional techniques undesirably reduce the overalltransmission of light wavelengths other than blue light wavelengths.This unwanted reduction may in turn result in reduced visual acuity fora lens user.

It has been found that conventional blue-blocking reduces visibletransmission, which in turn stimulates dilation of the pupil. Dilationof the pupil increases the flux of light to the internal eye structuresincluding the intraocular lens and retina. Since the radiant flux tothese structures increases as the square of the pupil diameter, a lensthat blocks half of the blue light but, with reduced visibletransmission, relaxes the pupil from 2 mm to 3 mm diameter will actuallyincrease the dose of blue photons to the retina by 12.5%. Protection ofthe retina from phototoxic light depends on the amount of this lightthat impinges on the retina, which depends on the transmissionproperties of the ocular media and also on the dynamic aperture of thepupil. Previous work to date has been silent on the contribution of thepupil to prophylaxis of phototoxic blue light.

Another problem with conventional blue-blocking is that it can degradenight vision. Blue light is more important for low-light level orscotopic vision than for bright light or photopic vision, a result whichis expressed quantitatively in the luminous sensitivity spectra forscotopic and photopic vision. Photochemical and oxidative reactionscause the absorption of 400 to 450 nm light by intraocular lens tissueto increase naturally with age. Although the number of rodphotoreceptors on the retina that are responsible for low-light visionalso decreases with age, the increased absorption by the intraocularlens is important to degrading night vision. For example, scotopicvisual sensitivity is reduced by 33% in a 53 year-old intraocular lensand 75% in a 75 year-old lens. The tension between retinal protectionand scotopic sensitivity is further described in Mainster and Sparrow,“How Much Light Should and IOL Transmit?” Br. J. Ophthalmol., 2003, v.87, pp. 1523-29.

Conventional approaches to blue blocking also may include cutoff orhigh-pass filters to reduce the transmission below a specified blue orviolet wavelength to zero. For example, all light below a thresholdwavelength may be blocked completely or almost completely. For example,U.S. Pub. Patent Application No. 2005/0243272 to Mainster and Mainster,“Intraocular Lenses Should Block UV Radiation and Violet but not BlueLight,” Arch. Ophthal., v. 123, p. 550 (2005) describe the blocking ofall light below a threshold wavelength between 400 and 450 nm. Suchblocking may be undesirable, since as the edge of the long-pass filteris shifted to longer wavelengths, dilation of the pupil acts to increasethe total flux. As previously described, this can degrade scotopicsensitivity and increase color distortion.

Recently there has been debate in the field of intraocular lenses (IOLs)regarding appropriate UV and blue light blocking while maintainingacceptable photopic vision, scotopic vision, color vision, and circadianrhythms.

In view of the foregoing, there is a need for an ophthalmic system thatcan provide one or more of the following:

1) Blue blocking with an acceptable level of blue light protection.

2) Acceptable color cosmetics, i.e., it is perceived as mostly colorneutral by someone observing the ophthalmic system when worn by awearer.

3) Acceptable color perception for a user. In particular, there is aneed for an ophthalmic system that will not impair the wearer's colorvision and further that reflections from the back surface of the systeminto the eye of the wearer be at a level of not being objectionable tothe wearer.

4) Acceptable level of light transmission for wavelengths other thanblue light wavelengths. In particular, there is a need for an ophthalmicsystem that allows for selective blockage of wavelengths of blue lightwhile at the same time transmitting in excess of 80% of visible light.

5) Acceptable photopic vision, scotopic vision, color vision, and/orcircadian rhythms.

This need exists as more and more data is pointing to blue light as oneof the possible contributory factors in macular degeneration (theleading cause of blindness in the industrialized world) and also otherretinal diseases.

SUMMARY OF THE INVENTION

According to the present invention, ophthalmic systems and coatings aredescribed comprising a selective light wavelength filter, wherein saidselective filter provides improved contrast sensitivity.

In some embodiments, an ophthalmic system comprising an ophthalmiccomponent and a filter is provided. The ophthalmic component may beselected from the group consisting of spectacle lens, contact lens,intra-ocular lens (IOL's), corneal grafts, corneal inlays, cornealonlays, and electro-active lens is provided. The system limits thetransmission of light of blue wavelengths in a wavelength range of430+/−10 nm by at least 10%. White light has CIE (x,y) coordinates of(0.33+/−0.05, 0.33+/−0.05) when transmitted through the system, and thetotal transmission of the system is greater than 90%.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features, and advantages of the present invention willbecome more apparent from the following detailed description of thepreferred embodiment and certain modifications thereof when takentogether with the accompanying drawings in which:

FIGS. 1A and 1B show examples of an ophthalmic system including aposterior blue blocking component and an anterior color balancingcomponent.

FIG. 2 shows an example of using a dye resist to form an ophthalmicsystem.

FIG. 3 illustrates an exemplary system with a blue blocking componentand a color balancing component integrated into a clear or mostly clearophthalmic lens.

FIG. 4 illustrates an exemplary ophthalmic system formed using anin-mold coating.

FIG. 5 illustrates the bonding of two ophthalmic components.

FIG. 6 illustrates exemplary ophthalmic systems using anti-reflectivecoatings.

FIGS. 7A-7C illustrates various exemplary combinations of a blueblocking component, a color balancing component, and an ophthalmiccomponent.

FIGS. 8A and 8B show examples of an ophthalmic system including amulti-functional blue blocking and color-balancing component.

FIG. 9 shows a reference of observed colors that correspond to variousCIE coordinates.

FIG. 10 shows the transmission of the GENTEX E465 absorbing dye.

FIG. 11 shows the absorbance of the GENTEX E465 absorbing dye.

FIG. 12 shows the transmittance of a polycarbonate substrate with a dyeconcentration suitable for absorbing in the 430 nm range.

FIG. 13 shows the transmittance as a function of wavelength of apolycarbonate substrate with an antireflective coating.

FIG. 14 shows the color plot of a polycarbonate substrate with anantireflective coating.

FIG. 15 shows the transmittance as a function of wavelength of anuncoated polycarbonate substrate and a polycarbonate substrate with anantireflective coating on both surfaces.

FIG. 16 shows the spectral transmittance of a 106 nm layer of TiO2 on apolycarbonate substrate.

FIG. 17 shows the color plot of a 106 nm layer of TiO2 on apolycarbonate substrate.

FIG. 18 shows the spectral transmittance of a 134 nm layer of TiO2 on apolycarbonate substrate.

FIG. 19 shows the color plot of a 134 nm layer of TiO2 on apolycarbonate substrate.

FIG. 20 shows the spectral transmittance of a modified AR coatingsuitable for color balancing a substrate having a blue absorbing dye.

FIG. 21 shows the color plot of a modified AR coating suitable for colorbalancing a substrate having a blue absorbing dye.

FIG. 22 shows the spectral transmittance of a substrate having a blueabsorbing dye.

FIG. 23 shows the color plot of a substrate having a blue absorbing dye.

FIG. 24 shows the spectral transmittance of a substrate having a blueabsorbing dye and a rear AR coating.

FIG. 25 shows the color plot of a substrate having a blue absorbing dyeand a rear AR coating.

FIG. 26 shows the spectral transmittance of a substrate having a blueabsorbing dye and AR coatings on the front and rear surfaces.

FIG. 27 shows the color plot of a substrate having a blue absorbing dyeand AR coatings on the front and rear surfaces.

FIG. 28 shows the spectral transmittance of a substrate having a blueabsorbing dye and a color balancing AR coating.

FIG. 29 shows the color plot of a substrate having a blue absorbing dyeand a color balancing AR coating.

FIG. 30 shows an exemplary ophthalmic device comprising a film.

FIG. 31 shows the optical transmission characteristic of an exemplaryfilm.

FIG. 32 shows an exemplary ophthalmic system comprising a film.

FIG. 33 shows an exemplary system comprising a film.

FIGS. 34A and 34B show pupil diameter and pupil area, respectively, as afunction of field illuminance.

FIG. 35 shows the transmission spectrum of a film that is doped withperylene dye where the product of concentration and path length yieldabout 33% transmission at about 437 nm.

FIG. 36 shows the transmission spectrum of a film according to thepresent invention with a perylene concentration about 2.27 times higherthan that illustrated in the previous figure.

FIG. 37 shows an exemplary transmission spectrum for a six-layer stackof SiO₂ and ZrO₂.

FIG. 38 shows reference color coordinates corresponding to Munsell tilesilluminated by a prescribed illuminant in (L*, a*, b*) color space.

FIG. 39A shows a histogram of the color shifts for Munsell color tilesfor a related filter. FIG. 39B shows a color shift induced by a relatedblue-blocking filter.

FIG. 40 shows a histogram of color shifts for a perylene-dyed substrateaccording to the present invention.

FIG. 41 shows the transmission spectrum of a system according to thepresent invention.

FIG. 42 shows a histogram summarizing color distortion of a deviceaccording to the present invention for Munsell tiles in daylight.

FIGS. 43A-43B show representative series of skin reflectance spectrafrom subjects of different races.

FIG. 44 shows an exemplary skin reflectance spectrum for a Caucasiansubject.

FIG. 45 shows transmission spectra for various lenses.

FIG. 46 shows exemplary dyes.

FIG. 47 shows an ophthalmic system having a hard coat.

FIG. 48 shows the transmittance as a function of wavelength for aselective filter with strong absorption band around 430 nm.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention relate to an ophthalmic system thatperforms effective blue blocking while at the same time providing acosmetically attractive product, normal or acceptable color perceptionfor a user, and a high level of transmitted light for good visualacuity. An ophthalmic system is provided that can provide an averagetransmission of 80% or better transmission of visible light, inhibitselective wavelengths of blue light (“blue blocking”), allow for thewearer's proper color vision performance, and provide a mostly colorneutral appearance to an observer looking at the wearer wearing such alens or lens system. As used herein, the “average transmission” of asystem refers to the average transmission at wavelengths in a range,such as the visible spectrum. A system also may be characterized by the“luminous transmission” of the system, which refers to an average in awavelength range, that is weighted according to the sensitivity of theeye at each wavelength. Systems described herein may use various opticalcoatings, films, materials, and absorbing dyes to produce the desiredeffect.

More specifically, embodiments of the invention may provide effectiveblue blocking in combination with color balancing. “Color balancing” or“color balanced” as used herein means that the yellow or amber color, orother unwanted effect of blue blocking is reduced, offset, neutralizedor otherwise compensated for so as to produce a cosmetically acceptableresult, without at the same time reducing the effectiveness of the blueblocking. For example, wavelengths at or near 400 nm-460 nm may beblocked or reduced in intensity. In particular, for example, wavelengthsat or near 420-440 nm may be blocked or reduced in intensity.Furthermore, transmission of unblocked wavelengths may remain at a highlevel, for example at least 80%. Additionally, to an external viewer,the ophthalmic system may look clear or mostly clear. For a system user,color perception may be normal or acceptable.

An “ophthalmic system” as used here includes prescription ornon-prescription ophthalmic lenses used, e.g., for clear or tintedglasses (or spectacles), sunglasses, contact lenses with and withoutvisibility and/or cosmetic tinting, intra-ocular lenses (IOLs), cornealgrafts, corneal inlays, corneal on-lays, and electro-active ophthalmicdevices and may be treated or processed or combined with othercomponents to provide desired functionalities described in furtherdetail herein. The invention can be formulated so as to allow beingapplied directly into corneal tissue.

As used herein, an “ophthalmic material” is one commonly used tofabricate an ophthalmic system, such as a corrective lens. Exemplaryophthalmic materials include glass, plastics such as CR-39, Trivex, andpolycarbonate materials, though other materials may be used and areknown for various ophthalmic systems.

An ophthalmic system may include a blue blocking component posterior toa color-balancing component. Either of the blue blocking component orthe color balancing component may be, or form part of, an ophthalmiccomponent such as a lens. The posterior blue blocking component andanterior color balancing component may be distinct layers on or adjacentto or near a surface or surfaces of an ophthalmic lens. Thecolor-balancing component may reduce or neutralize a yellow or ambertint of the posterior blue blocking component, to produce a cosmeticallyacceptable appearance. For example, to an external viewer, theophthalmic system may look clear or mostly clear. For a system user,color perception may be normal or acceptable. Further, because the blueblocking and color balancing tints are not intermixed, wavelengths inthe blue light spectrum may be blocked or reduced in intensity and thetransmitted intensity of incident light in the ophthalmic system may beat least 80% for unblocked wavelengths.

As discussed previously, techniques for blue blocking are known. Theknown techniques to block blue light wavelengths include absorption,reflection, interference, or any combination thereof. As discussedearlier, according to one technique, a lens may be tinted/dyed with ablue blocking tint, such as BPI Filter Vision 450 or BPI Diamond Dye500, in a suitable proportion or concentration. The tinting may beaccomplished, for example, by immersing the lens in a heated tint potcontaining a blue blocking dye solution for some predetermined period oftime. According to another technique, a filter is used for blueblocking. The filter could include, for example, organic or inorganiccompounds exhibiting absorption and/or reflection of and/or interferencewith blue light wavelengths. The filter could comprise multiple thinlayers or coatings of organic and/or inorganic substances. Each layermay have properties, which, either individually or in combination withother layers, absorbs, reflects or interferes with light having bluelight wavelengths. Rugate notch filters are one example of blue blockingfilters. Rugate filters are single thin films of inorganic dielectricsin which the refractive index oscillates continuously between high andlow values. Fabricated by the co-deposition of two materials ofdifferent refractive index (e.g. SiO₂ and TiO₂), rugate filters areknown to have very well defined stop-bands for wavelength blocking, withvery little attenuation outside the band. The construction parameters ofthe filter (oscillation period, refractive index modulation, number ofrefractive index oscillations) determine the performance parameters ofthe filter (center of the stop-band, width of the stop band,transmission within the band). Rugate filters are disclosed in moredetail in, for example, U.S. Pat. Nos. 6,984,038 and 7,066,596, each ofwhich is incorporated by reference in its entirety. Another techniquefor blue blocking is the use of multi-layer dielectric stacks.Multi-layer dielectric stacks are fabricated by depositing discretelayers of alternating high and low refractive index materials. Similarlyto rugate filters, design parameters such as individual layer thickness,individual layer refractive index, and number of layer repetitionsdetermine the performance parameters for multi-layer dielectric stacks.

Color balancing may comprise imparting, for example, a suitableproportion or concentration of blue tinting/dye, or a suitablecombination of red and green tinting/dyes to the color-balancingcomponent, such that when viewed by an external observer, the ophthalmicsystem as a whole has a cosmetically acceptable appearance. For example,the ophthalmic system as a whole may look clear or mostly clear.

FIG. 1A shows an ophthalmic system including a posterior blue blockingcomponent 101 and an anterior color-balancing component 102. Eachcomponent has a concave posterior side or surface 110, 115 and a convexanterior side or surface 120, 125. In system 100, the posterior blueblocking component 101 may be or include an ophthalmic component, suchas a single vision lens, wafer or optical pre-form. The single visionlens, wafer or optical pre-form may be tinted or dyed to perform blueblocking. The anterior color-balancing component 102 may comprise asurface cast layer, applied to the single vision lens, wafer or opticalpre-form according to known techniques. For example, the surface castlayer may be affixed or bonded to the single vision lens, wafer oroptical pre-form using visible or UV light, or a combination of the two.

The surface cast layer may be formed on the convex side of the singlevision lens, wafer or optical pre-form. Since the single vision lens,wafer or optical pre-form has been tinted or dyed to perform blueblocking, it may have a yellow or amber color that is undesirablecosmetically. Accordingly, the surface cast layer may, for example, betinted with a suitable proportion of blue tinting/dye, or a suitablecombination of red and green tinting/dyes.

The surface cast layer may be treated with color balancing additivesafter it is applied to the single vision lens, wafer or optical pre-formthat has already been processed to make it blue blocking. For example,the blue blocking single vision lens, wafer or optical pre-form with thesurface cast layer on its convex surface may be immersed in a heatedtint pot which has the appropriate proportions and concentrations ofcolor balancing dyes in a solution. The surface cast layer will take upthe color balancing dyes from the solution. To prevent the blue blockingsingle vision lens, wafer or optical pre-form from absorbing any of thecolor balancing dyes, its concave surface may be masked or sealed offwith a dye resist, e.g. tape or wax or other coating. This isillustrated in FIG. 2 , which shows an ophthalmic system 100 with a dyeresist 201 on the concave surface of the single vision lens, wafer oroptical pre-form 101. The edges of the single vision lens, wafer oroptical pre-form may be left uncoated to allow them to becomecosmetically color adjusted. This may be important for negative focallenses having thick edges.

FIG. 1B shows another ophthalmic system 150 in which the anteriorcolor-balancing component 104 may be or include an ophthalmic component,such as a single vision or multi-focal lens, wafer or optical pre-form.The posterior blue blocking component 103 may be a surface cast layer.To make this combination, the convex surface of the color balancingsingle vision lens, wafer or optical pre-form may be masked with a dyeresist as described above, to prevent it taking up blue blocking dyeswhen the combination is immersed in a heated tint pot containing a blueblocking dye solution. Meanwhile, the exposed surface cast layer willtake up the blue blocking dyes.

It should be understood that the surface cast layer could be used incombination with a multi-focal, rather than a single vision, lens, waferor optical pre-form. In addition, the surface cast layer could be usedto add power to a single vision lens, wafer or optical pre-form,including multi-focal power, thus converting the single vision lens,wafer or optical pre-form to a multi-focal lens, with either a lined orprogressive type addition. Of course, the surface cast layer could alsobe designed to add little or no power to the single vision lens, waferor optical pre-form.

FIG. 3 shows blue blocking and color balancing functionality integratedinto an ophthalmic component. More specifically, in ophthalmic lens 300,a portion 303 corresponding to a depth of tint penetration into anotherwise clear or mostly clear ophthalmic component 301 at a posteriorregion thereof may be blue blocking. Further, a portion 302,corresponding to a depth of tint penetration into the otherwise clear ormostly clear ophthalmic component 301 at a frontal or anterior regionthereof may be color balancing. The system illustrated in FIG. 3 may beproduced as follows. The ophthalmic component 301 may, for example,initially be a clear or mostly clear single vision or multi-focal lens,wafer or optical pre-form. The clear or mostly clear single vision ormulti-focal lens, wafer or optical pre-form may be tinted with a blueblocking tint while its front convex surface is rendered non-absorptive,e.g., by masking or coating with a dye resist as described previously.As a result, a portion 303, beginning at the posterior concave surfaceof the clear or mostly clear single vision or multi-focal lens, wafer oroptical pre-form 301 and extending inwardly, and having blue blockingfunctionality, may be created by tint penetration. Then, theanti-absorbing coating of the front convex surface may be removed. Ananti-absorbing coating may then be applied to the concave surface, andthe front convex surface and peripheral edges of the single vision ormulti-focal lens, wafer or optical pre-form may be tinted (e.g. byimmersion in a heated tint pot) for color balancing. The color balancingdyes will be absorbed by the peripheral edges and a portion 302beginning at the front convex surface and extending inwardly, that wasleft un-tinted due to the earlier coating. The order of the foregoingprocess could be reversed, i.e., the concave surface could first bemasked while the remaining portion was tinted for color balancing. Then,the coating could be removed and a depth or thickness at the concaveregion left un-tinted by the masking could be tinted for blue blocking.

Referring now to FIG. 4 , an ophthalmic system 400 may be formed usingan in-mold coating. More specifically, an ophthalmic component 401 suchas a single vision or multi-focal lens, wafer or optical pre-form whichhas been dyed/tinted with a suitable blue blocking tint, dye or otheradditive may be color balanced via surface casting using a tintedin-mold coating 403. The in-mold coating 403, comprising a suitablelevel and/or mixtures of color balancing dyes, may be applied to theconvex surface mold (i.e., a mold, not shown, for applying the coating403 to the convex surface of the ophthalmic component 401). A colorlessmonomer 402 may be filled in and cured between the coating 403 andophthalmic component 401. The process of curing the monomer 402 willcause the color balancing in-mold coating to transfer itself to theconvex surface of the ophthalmic component 401. The result is a blueblocking ophthalmic system with a color balancing surface coating. Thein-mold coating could be, for example, an anti-reflective coating or aconventional hard coating.

Referring now to FIG. 5 , an ophthalmic system 500 may comprise twoophthalmic components, one blue blocking and the other color balancing.For example, a first ophthalmic component 501 could be a back singlevision or concave surface multi-focal lens, wafer or optical pre-form,dyed/tinted with the appropriate blue blocking tint to achieve thedesired level of blue blocking. A second ophthalmic component 503 couldbe a front single vision or convex surface multi-focal lens, wafer oroptical pre-form, bonded or affixed to the back single vision or concavesurface multi-focal lens, wafer or optical pre-form, for example using aUV or visible curable adhesive 502. The front single vision or convexsurface multi-focal lens, wafer or optical pre-form could be renderedcolor balancing either before or after it was bonded with the backsingle vision or concave surface multi-focal lens, wafer or opticalpre-form. If after, the front single vision or convex surfacemulti-focal lens, wafer or optical pre-form could be rendered colorbalancing, for example, by techniques described above. For example, theback single vision or concave surface multi-focal lens, wafer or opticalpre-form may be masked or coated with a dye resist to prevent it takingup color balancing dyes. Then, the bonded back and front portions may betogether placed in a heated tint pot containing a suitable solution ofcolor balancing dyes, allowing the front portion to take up colorbalancing dyes.

Any of the above-described embodiments systems, may be combined with oneor more anti-reflective (AR) components. This is shown in FIG. 6 , byway of example, for the ophthalmic lenses 100 and 150 shown in FIGS. 1Aand 1B. In FIG. 6 , a first AR component 601, e.g. a coating, is appliedto the concave surface of posterior blue blocking element 101, and asecond AR component 602 is applied to the convex surface of colorbalancing component 102. Similarly, a first AR component 601 is appliedto the concave surface of posterior blue blocking component 103, and asecond AR component 602 is applied to the convex surface of colorbalancing component 104.

FIGS. 7A-7C show further exemplary systems including a blue blockingcomponent and a color-balancing component. In FIG. 7A, an ophthalmicsystem 700 includes a blue blocking component 703 and a color balancingcomponent 704 that are formed as adjacent, but distinct, coatings orlayers on or adjacent to the anterior surface of a clear or mostly clearophthalmic lens 702. The blue blocking component 703 is posterior to thecolor-balancing component 704. On or adjacent to the posterior surfaceof the clear or mostly clear ophthalmic lens, an AR coating or otherlayer 701 may be formed. Another AR coating or layer 705 may be formedon or adjacent to the anterior surface of the color-balancing layer 704.

In FIG. 7B, the blue blocking component 703 and color-balancingcomponent 704 are arranged on or adjacent to the posterior surface ofthe clear or mostly clear ophthalmic lens 702. Again, the blue blockingcomponent 703 is posterior to the color-balancing component 704. An ARcomponent 701 may be formed on or adjacent to the posterior surface ofthe blue blocking component 703. Another AR component 705 may be formedon or adjacent to the anterior surface of the clear or mostly clearophthalmic lens 702.

In FIG. 7C, the blue blocking component 703 and the color-balancingcomponent 704 are arranged on or adjacent to the posterior and theanterior surfaces, respectively, of the clear ophthalmic lens 702.Again, the blue blocking component 703 is posterior to thecolor-balancing component 704. An AR component 701 may be formed on oradjacent to the posterior surface of the blue blocking component 703,and another AR component 705 may be formed on or adjacent to theanterior surface of the color-balancing component 704.

FIGS. 8A and 8B show an ophthalmic system 800 in which functionality toboth block blue light wavelengths and to perform color balancing may becombined in a single component 803. For example, the combinedfunctionality component may block blue light wavelengths and reflectsome green and red wavelengths as well, thus neutralizing the blue andeliminating the appearance of a dominant color in the lens. The combinedfunctionality component 803 may be arranged on or adjacent to either theanterior or the posterior surface of a clear ophthalmic lens 802. Theophthalmic lens 800 may further include an AR component 801 on oradjacent to either the anterior or the posterior surface of the clearophthalmic lens 802.

To quantify the effectiveness of a color balancing component, it may beuseful to observe light reflected and/or transmitted by a substrate ofan ophthalmic material. The observed light may be characterized by itsInternational Commission on Illumination (CIE) coordinates to indicatethe color of observed light; by comparing these coordinates to the CIEcoordinates of the incident light, it is possible to determine how muchthe color of the light was shifted due to the reflection/transmission.White light is defined to have CIE coordinates of (0.33, 0.33). Thus,the closer an observed light's CIE coordinates are to (0.33, 0.33), the“more white” it will appear to an observer. To characterize the colorshifting or balancing performed by a lens, (0.33, 0.33) white light maybe directed at the lens, and the CIE of reflected and transmitted lightobserved. If the transmitted light has a CIE of about (0.33, 0.33),there will be no color shifting, and items viewed through the lens willhave a natural appearance, i.e., the color will not be shifted relativeto items observed without the lens. Similarly, if the reflected lighthas a CIE of about (0.33, 0.33), the lens will have a natural cosmeticappearance, i.e., it will not appear tinted to an observer viewing auser of the lens or ophthalmic system. Thus, it is desirable fortransmitted and reflected light to have a CIE as close to (0.33, 0.33)as possible.

FIG. 9 shows a CIE plot indicating the observed colors corresponding tovarious CIE coordinates. A reference point 900 indicates the coordinates(0.33, 0.33). Although the central region of the plot typically isdesignated as “white,” some light having CIE coordinates in this regioncan appear slightly tinted to a viewer. For example, light having CIEcoordinates of (0.4, 0.4) will appear yellow to an observer. Thus, toachieve a color-neutral appearance in an ophthalmic system, it isdesirable for (0.33, 0.33) light (i.e., white light) that is transmittedand/or reflected by the system to have CIE coordinates as close to(0.33, 0.33) as possible after the transmission/reflection. The CIE plotshown in FIG. 9 will be used herein as a reference to show the colorshifts observed with various systems, though the labeled regions will beomitted for clarity.

Absorbing dyes may be included in the substrate material of anophthalmic lens by injection molding the dye into the substrate materialto produce lenses with specific light transmission and absorptionproperties. These dye materials can absorb at the fundamental peakwavelength of the dye or at shorter resonance wavelengths due to thepresence of a Soret band typically found in porphyrin materials.Exemplary ophthalmic materials include various glasses and polymers suchas CR39™, TRIVEX™, polycarbonate, polymethylmethacrylate, silicone, andfluoropolymers, though other materials may be used and are known forvarious ophthalmic systems.

By way of example only, GENTEX™ day material E465 transmittance andabsorbance is shown in FIGS. 10-11 . The Absorbance (A) is related tothe transmittance (T) by the equation, A=log₁₀(1/T). In this case, thetransmittance is between 0 and 1 (0<T<1). Often transmittance is expressas a percentage, i.e., 0%<T<100%. The E465 dye blocks those wavelengthsless than 465 and is normally provided to block these wavelengths withhigh optical density (OD>4). Similar products are available to blockother wavelengths. For example, E420 from GENTEX™ blocks wavelengthsbelow 420 nm. Other exemplary dyes include porphyrins, perylene, andsimilar dyes that can absorb at blue wavelengths.

The absorbance at shorter wavelengths can be reduced by a reduction ofthe dye concentration. This and other dye materials can achieve atransmittance of about 50% in the 430 nm region.

FIG. 12 shows the transmittance of a polycarbonate substrate with a dyeconcentration suitable for absorbing in the 430 nm range, and with someabsorption in the range of 420 nm-440 nm. This was achieved by reducingthe concentration of the dye and including the effects of apolycarbonate substrate. The rear surface is at this point notantireflection coated.

The concentration of dye also may affect the appearance and color shiftof an ophthalmic system. By reducing the concentration, systems withvarying degrees of color shift may be obtained. A “color shift” as usedherein refers to the amount by which the CIE coordinates of a referencelight change after transmission and/or reflection of the ophthalmicsystem. It also may be useful to characterize a system by the colorshift causes by the system due to the differences in various types oflight typically perceived as white (e.g., sunlight, incandescent light,and fluorescent light). It therefore may be useful to characterize asystem based on the amount by which the CIE coordinates of incidentlight are shifted when the light is transmitted and/or reflected by thesystem. For example, a system in which light with CIE coordinates of(0.33, 0.33) becomes light with a CIE of (0.30, 0.30) after transmissionmay be described as causing a color shift of (−0.03, −0.03), or, moregenerally, (+/−0.03, +/−0.03). Thus the color shift caused by a systemindicates how “natural” light and viewed items appear to a wearer of thesystem. As further described below, systems causing color shifts of lessthan (+/−0.05, +/−0.05) to (+/−0.02, +/−0.02) have been achieved.

A reduction in short-wavelength transmission in an ophthalmic system maybe useful in reducing cell death due to photoelectric effects in theeye, such as excitation of A2E. It has been shown that reducing incidentlight at 430+/−30 nm by about 50% can reduce cell death by about 80%.See, for example, Janet R. Sparrow et al., “Blue light-absorbingintraocular lens and retinal pigment epithelium protection in vitro,” J.Cataract Refract. Surg. 2004, vol. 30, pp. 873-78, the disclosure ofwhich is incorporated by reference in its entirety. It is furtherbelieved that reducing the amount of blue light, such as light in the430-460 nm range, by as little as 5% may similarly reduce cell deathand/or degeneration, and therefore prevent or reduce the adverse effectsof conditions such as atrophic age-related macular degeneration.

Although an absorbing dye may be used to block undesirable wavelengthsof light, the dye may produce a color tint in the lens as a side effect.For example, many blue-blocking ophthalmic lenses have a yellow coloringthat is often undesirable and/or aesthetically displeasing. To offsetthis coloring, a color balancing coating may be applied to one or bothsurfaces of a substrate including the absorbing dye therein.

Antireflection (AR) coatings (which are interference filters) arewell-established within the commercial ophthalmic coating industry. Thecoatings typically are a few layers, often less than 10, and typicallyare used to reduce the reflection from the polycarbonate surface to lessthan 1%. An example plot of transmittance (%) versus wavelength (nm) forsuch a coating on a polycarbonate surface is shown in FIG. 13 . Thecolor plot of this coating is shown in FIG. 14 and it is observed thatthe color is quite neutral. The total reflectance was observed to be0.21%. The reflected light was observed to have CIE coordinates of(0.234, 0.075); the transmitted light had CIE coordinates of (0.334,0.336).

AR coatings may be applied to both surfaces of a lens or otherophthalmic device to achieve a higher transmittance. Such aconfiguration is shown in FIG. 15 where the darker line 1510 is the ARcoated polycarbonate and the thinner line 1520 is an uncoatedpolycarbonate substrate. This AR coating provides a 10% increase intotal transmitted light. There is some natural loss of light due toabsorption in the polycarbonate substrate. The particular polycarbonatesubstrate used for this example has a transmittance loss ofapproximately 3%. In the ophthalmic industry AR coatings generally areapplied to both surfaces to increase the transmittance of the lens.

In systems according to the present invention, AR coatings or othercolor balancing films may be combined with an absorbing dye to allow forsimultaneous absorption of blue wavelength light, typically in the 430nm region, and increased transmittance. As previously described,elimination of the light in the 430 nm region alone typically results ina lens that has some residual color cast. To spectrally tailor the lightto achieve a color neutral transmittance, at least one of the ARcoatings may be modified to adjust the overall transmitted color of thelight. In ophthalmic systems according to the invention, this adjustmentmay be performed on the front surface of the lens to create thefollowing lens structure:

Air (farthest from the user's eye)/Front convex lens coating/Absorbingophthalmic lens substrate/rear concave anti-reflection coating/Air(closest to the user's eye).

In such a configuration, the front coating may provide spectraltailoring to offset the color cast resulting from the absorption in thesubstrate in addition to the antireflective function typically performedin conventional lenses. The lens therefore may provide an appropriatecolor balance for both transmitted and reflected light. In the case oftransmitted light the color balance allows for proper color vision; inthe case reflected light the color balance may provide the appropriatelens aesthetics.

In some cases, a color balancing film may be disposed between two layersof other ophthalmic material. For example, a filter, AR film, or otherfilm may be disposed within an ophthalmic material. For example, thefollowing configuration may be used:

Air (farthest from the user's eye)/ophthalmic material/film/ophthalmicmaterial/air (closest to user's eye).

The color balancing film also may be a coating, such as a hardcoat,applied to the outer and/or inner surface of a lens. Otherconfigurations are possible. For example, referring to FIG. 3 , anophthalmic system may include an ophthalmic material 301 doped with ablue-absorbing dye and one or more color balancing layers 302, 303. Inanother configuration, an inner layer 301 may be a color balancing layersurrounded by ophthalmic material 302, 303 doped with a blue-absorbingdye. Additional layers and/or coatings, such as AR coatings, may bedisposed on one or more surfaces of the system. It will be understoodhow similar materials and configurations may be used, for example in thesystems described with respect to FIGS. 4-8B.

Thus, optical films and/or coatings such as AR coatings may be used tofine-tune the overall spectral response of a lens having an absorbingdye. Transmission variation across the visible spectrum is well knownand varies as a function of the thickness and number of layers in theoptical coating. In the invention one or more layers can be used toprovide the needed adjustment of the spectral properties.

In an exemplary system, color variation is produced by a single layer ofTiO₂ (a common AR coating material).

FIG. 16 shows the spectral transmittance of a 106 nm thick single layerof TiO₂. The color plot of this same layer is shown in FIG. 17 . The CIEcolor coordinates (x, y) 1710 shown for the transmitted light are (0.331, 0.345). The reflected light had CIE coordinates of (0.353, 0.251)1720, resulting in a purplish-pink color.

Changing the thickness of the TiO₂ layer changes the color of thetransmitted light as shown in the transmitted spectra and color plot fora 134 nm layer, shown in FIGS. 18 and 19 respectively. In this system,the transmitted light exhibited CIE coordinates of (0.362, 0.368) 1910,and the reflected light had CIE coordinates of (0.209, 0.229) 1920. Thetransmission properties of various AR coatings and the prediction orestimation thereof are known in the art. For example, the transmissioneffects of an AR coating formed of a known thickness of an AR materialmay be calculated and predicted using various computer programs.Exemplary, non-limiting programs include Essential Macleod Thin FilmsSoftware available from Thin Film Center, Inc., TFCalc available fromSoftware Spectra, Inc., and FilmStar Optical Thin Film Softwareavailable from FTG Software Associates. Other methods may be used topredict the behavior of an AR coating or other similar coating or film.

In systems according to the present invention, a blue-absorbing dye maybe combined with a coating or other film to provide a blue blocking,color balanced system. The coating may be an AR coating on the frontsurface that is modified to correct the color of the transmitted and/orreflected light. The transmittance and color plot of an exemplary ARcoating are shown in FIGS. 20 and 21 , respectively. FIGS. 22 and 23show the transmittance and color plot, respectively, for a polycarbonatesubstrate having a blue absorbing dye without an AR coating. The dyedsubstrate absorbs most strongly in the 430 nm region, including someabsorption in the 420-440 nm region. The dyed substrate may be combinedwith an appropriate AR coating as illustrated in FIGS. 20-21 to increasethe overall transmittance of the system. The transmittance and colorplot for a dyed substrate having a rear AR coating are shown in FIGS. 24and 25 , respectively.

An AR coating also may be applied to the front of an ophthalmic system(i.e., the surface farthest from the eye of a wearer of the system),resulting in the transmittance and color plot shown in FIGS. 26 and 27 ,respectively. Although the system exhibits a high transmission andtransmitted light is relatively neutral, the reflected light has a CIEof (0.249, 0.090). Therefore, to more completely color balance theeffects of the blue absorbing dye, the front AR coating may be modifiedto achieve the necessary color balance to produce a color neutralconfiguration. The transmittance and the color plot of thisconfiguration are shown in FIGS. 28 and 29 respectively. In thisconfiguration, both the transmitted and reflected light may be optimizedto achieve color neutrality. It may be preferred for the interiorreflected light to be about 6%. Should the reflectivity level beannoying to the wearer of the system, the reflection can be furtherreduced by way of adding an additional different absorbing dye into thelens substrate that would absorb a different wavelength of visiblelight. However, the design of this configuration achieves remarkableperformance and satisfies the need for a blue blocking, color balancedophthalmic system as described herein. The total transmittance is over90% and both the transmitted and reflected colors are quite close to thecolor neutral white point. As shown in FIG. 27 , the reflected light hasa CIE of (0.334, 0.334), and the transmitted light has a CIE of (0.341,0.345), indicating little or no color shifting.

In some configurations, the front modified anti-reflection coating canbe designed to block 100% of the blue light wave length to be inhibited.However, this may result in a back reflection of about 9% to 10% for thewearer. This level of reflectivity can be annoying to the wearer. Thusby combining an absorbing dye into the lens substrate this reflectionwith the front modified anti-reflection coating the desired effect canbe achieved along with a reduction of the reflectivity to a level thatis well accepted by the wearer. The reflected light observed by a wearerof a system including one or more AR coatings may be reduced to 8% orless, or more preferably 3% or less.

The combination of a front and rear AR coating may be referred to as adielectric stack, and various materials and thicknesses may be used tofurther alter the transmissive and reflective characteristics of anophthalmic system. For example, the front AR coating and/or the rear ARcoating may be made of different thicknesses and/or materials to achievea particular color balancing effect. In some cases, the materials usedto create the dielectric stack may not be materials traditionally usedto create antireflective coatings. That is, the color balancing coatingsmay correct the color shift caused by a blue absorbing dye in thesubstrate without performing an antireflective function.

As discussed previously, filters are another technique for blueblocking. Accordingly, any of the blue blocking components discussedcould be or include or be combined with blue blocking filters. Suchfilters may include rugate filters, interference filters, band-passfilters, band-block filters, notch filters or dichroic filters.

In embodiments of the invention, one or more of the above-disclosedblue-blocking techniques may be used in conjunction with otherblue-blocking techniques. By way of example only, a lens or lenscomponent may utilize both a dye/tint and a rugate notch filter toeffectively block blue light.

Any of the above-disclosed structures and techniques may be employed inan ophthalmic system according to the present invention to performblocking of blue light wavelengths at or near 400-460 nm. For example,in embodiments the wavelengths of blue light blocked may be within apredetermined range. In embodiments, the range may be 430 nm+/−30 nm. Inother embodiments, the range may be 430 nm+/−20 nm. In still otherembodiments, the range may be 430 nm+/−10 nm. In embodiments, theophthalmic system may limit transmission of blue wavelengths within theabove-defined ranges to substantially 90% of incident wavelengths. Inother embodiments, the ophthalmic system may limit transmission of theblue wavelengths within the above-defined ranges to substantially 80% ofincident wavelengths. In other embodiments, the ophthalmic system maylimit transmission of the blue wavelengths within the above-definedranges to substantially 70% of incident wavelengths. In otherembodiments, the ophthalmic system may limit transmission of the bluewavelengths within the above-defined ranges to substantially 60% ofincident wavelengths. In other embodiments, the ophthalmic system maylimit transmission of the blue wavelengths within the above-definedranges to substantially 50% of incident wavelengths. In otherembodiments, the ophthalmic system may limit transmission of the bluewavelengths within the above-defined ranges to substantially 40% ofincident wavelengths. In still other embodiments, the ophthalmic systemmay limit transmission of the blue wavelengths within the above-definedranges to substantially 30% of incident wavelengths. In still otherembodiments, the ophthalmic system may limit transmission of the bluewavelengths within the above-defined ranges to substantially 20% ofincident wavelengths. In still other embodiments, the ophthalmic systemmay limit transmission of the blue wavelengths within the above-definedranges to substantially 10% of incident wavelengths. In still otherembodiments, the ophthalmic system may limit transmission of the bluewavelengths within the above-defined ranges to substantially 5% ofincident wavelengths. In still other embodiments, the ophthalmic systemmay limit transmission of the blue wavelengths within the above-definedranges to substantially 1% of incident wavelengths. In still otherembodiments, the ophthalmic system may limit transmission of the bluewavelengths within the above-defined ranges to substantially 0% ofincident wavelengths. Stated otherwise, attenuation by the ophthalmicsystem of the electromagnetic spectrum at wavelengths in theabove-specified ranges may be at least 10%; or at least 20%; or at least30%; or at least 40%; or at least 50%; or at least 60%; or at least 70%;or at least 80%; or at least 90%; or at least 95%; or at least 99%; orsubstantially 100%.

In some cases it may be particularly desirable to filter a relativelysmall portion of the blue spectrum, such as the 400 nm-460 nm region.For example, it has been found that blocking too much of the bluespectrum can interfere with scotopic vision and circadian rhythms.Conventional blue blocking ophthalmic lenses typically block a muchlarger amount of a wide range of the blue spectrum, which can adverselyaffect the wearer's “biological clock” and have other adverse effects.Thus, it may be desirable to block a relatively narrow range of the bluespectrum as described herein. Exemplary systems that may filter arelatively small amount of light in a relatively small range includesystem that block or absorb 5-50%, 5-20%, and 5-10% of light having awavelength of 400 nm-460 nm, 410 nm-450 nm, and 420 nm-440 nm.

At the same time as wavelengths of blue light are selectively blocked asdescribed above, at least 80%, at least 85%, at least 90%, or at least95% of other portions of the visual electromagnetic spectrum may betransmitted by the ophthalmic system. Stated otherwise, attenuation bythe ophthalmic system of the electromagnetic spectrum at wavelengthsoutside the blue light spectrum, e.g. wavelengths other than those in arange around 430 nm may be 20% or less, 15% or less, 10% or less, and inother embodiments, 5% or less.

Additionally, embodiments of the present invention may further blockultra-violet radiation the UVA and UVB spectral bands as well asinfra-red radiation with wavelengths greater than 700 nm.

Any of the above-disclosed ophthalmic system may be incorporated into anarticle of eyewear, including externally-worn eyewear such aseyeglasses, sunglasses, goggles or contact lenses. In such eyewear,because the blue-blocking component of the systems is posterior to thecolor balancing component, the blue-blocking component will always becloser to the eye than the color-balancing component when the eyewear isworn. The ophthalmic system may also be used in such articles ofmanufacture as surgically implantable intra-ocular lenses.

Several embodiments use a film to block the blue light. The film in anophthalmic or other system may selectively inhibit at least 5%, at least10%, at least 20%, at least 30%, at least 40%, and/or at least 50% ofblue light within the 400 nm-460 nm range. As used herein, a film“selectively inhibits” a wavelength range if it inhibits at least sometransmission within the range, while having little or no effect ontransmission of visible wavelengths outside the range. The film and/or asystem incorporating the film may be color balanced to allow for beingperception by an observer and/or user as colorless. Systemsincorporating a film according to the present invention may have ascotopic luminous transmission of 85% or better of visible light, andfurther allow someone looking through the film or system to have mostlynormal color vision.

FIG. 30 shows an exemplary embodiment of the present invention. A film3002 may be disposed between two layers or regions of one or more basematerials 3001, 3003. As further described herein, the film may containa dye that selectively inhibits certain wavelengths of light. The basematerial or materials may be any material suitable for a lens,ophthalmic system, window, or other system in which the film may bedisposed.

The optical transmission characteristic of an exemplary film accordingto the invention is shown in FIG. 31 where about 50% of blue light inthe range of 430 nm+/−10 nm is blocked, while imparting minimal losseson other wavelengths within the visible spectrum. The transmission shownin FIG. 31 is exemplary, and it will be understood that for manyapplications it may be desirable to selectively inhibit less than 50% ofblue light, and/or the specific wavelengths inhibited may vary. It isbelieved that in many applications cell death may be reduced orprevented by blocking less than 50% of blue light. For example, it maybe preferred to selectively inhibit about 40%, more preferably about30%, more preferably about 20%, more preferably about 10%, and morepreferably about 5% of light in the 400-460 nm range. Selectivelyinhibiting a smaller amount of light may allow for prevention of damagedue to high-energy light, while being minimal enough that the inhibitiondoes not adversely affect scotopic vision and/or circadian cycles in auser of the system.

FIG. 32 shows a film 3201 incorporated into an ophthalmic lens 3200according to the present invention, where it is sandwiched betweenlayers of ophthalmic material 3202, 3203. The thickness of the frontlayer of ophthalmic material is, by way of example only, in the range of200 microns to 1,000 microns.

Similarly, FIG. 33 shows an exemplary system 3300, such as an automotivewindshield, according to the present invention. A film 3301 may beincorporated into the system 3300, where it is sandwiched between layersof base material 3302, 3303. For example, where the system 3300 is anautomotive windshield, the base material 3302, 3303 may be windshieldglass as is commonly used. It will be understood that in various othersystems, including visual, display, ophthalmic, and other systems,different base materials may be used without departing from the scope ofthe present invention.

In an embodiment, a system according to the invention may be operated inan environment where the relevant emitted visible light has a veryspecific spectrum. In such a regime, it may be desirable to tailor afilm's filtering effect to optimize the light transmitted, reflected, oremitted by the item. This may be the case, for example, where the colorof the transmitted, reflected, or emitted light is of primary concern.For example, when a film according to the present invention is used inor with a camera flash or flash filter, it may be desirable for theperceived color of the image or print to be as close to true color aspossible. As another example, a film according to the present inventionmay be used in instrumentation for observing the back of a patient's eyefor disease. In such a system, it may be important for the film not tointerfere with the true and observed color of the retina. As anotherexample, certain forms of artificial lighting may benefit from awavelength-customized filter utilizing the inventive film.

In an embodiment, the inventive film may be utilized within aphotochromatic, electro-chromic, or changeable tint ophthalmic lens,window or automotive windshield. Such a system may allow for protectionfrom UV light wavelengths, direct sunlight intensity, and blue lightwavelengths in an environment where the tinting is not active. In thisembodiment the film's blue light wavelengths protective attributes maybe effective regardless of whether the tinting is active.

In an embodiment, a film may allow for selective inhibition of bluelight while being color balanced and will have an 85% or greaterscotopic luminous transmission of visible light. Such a film may beuseful for lower light transmission uses such as driving glasses orsport glasses, and may provide increased visual performance due toincreased contrast sensitivity.

For some applications, it may be desirable for a system according to thepresent invention to selectively inhibit blue light as described herein,and have a luminous transmission of less than about 85%, typically about80-85%, across the visible spectrum. This may be the case where, forexample, a base material used in the system inhibits more light acrossall visible wavelengths due to its higher index of refraction. As aspecific example, high index (e.g., 1.7) lenses may reflect more lightacross wavelengths leading to a luminous transmission less than 85%.

To avoid, reduce, or eliminate problems present in conventionalblue-blocking systems, it may be desirable to reduce, but not eliminate,transmission of phototoxic blue light. The pupil of the eye responds tothe photopic retinal illuminance, in trolands, which is the product ofthe incident flux with the wavelength-dependent sensitivity of theretina and the projected area of the pupil. A filter placed in front ofthe retina, whether within the eye, as in an intraocular lens, attachedto the eye, as in a contact lens or corneal replacement, or otherwise inthe optical path of the eye as in a spectacle lens, may reduce the totalflux of light to the retina and stimulate dilation of the pupil, andthus compensate for the reduction in field illuminance. When exposed toa steady luminance in the field the pupil diameter generally fluctuatesabout a value that increases as the luminance falls.

A functional relationship between pupil area and field illuminancedescribed by Moon and Spencer, J. Opt. Soc. Am. v. 33, p. 260 (1944)using the following equation for pupil diameter:d=4.9−3 tan h(Log(L)+1)  (0.1)where d is in millimeters and L is the illuminance in cd/m². FIG. 34Ashows pupil diameter (mm) as a function of field illuminance (cd/m²).FIG. 34B shows pupil area (mm²) as a function of field illuminance.

The illuminance is defined by the international CIE standards as aspectrally weighted integration of visual sensitivity over wavelength:L=K _(m) ∫L _(e) γ,V _(γ) dγ photopicL′=K′ _(m) ∫L _(e) γ,V′ _(γ) dγ scotopic  (0.2)where K′_(m) is equal to 1700.06 lm/W for scotopic (night) vision,K_(m)=683.2 lm/W for photopic (day) vision and the spectral luminousefficiency functions V_(γ) and V′_(γ) define the standard photopic andscotopic observers. The luminous efficiency functions V_(γ) and V′_(γ)are illustrated in, e.g., FIG. 9 of Michael Kalloniatis and Charles Luu,“Psychophysics of Vision,” available athttp://webvision.med.utah.edu/Phychl.html, last visited Aug. 8, 2007,which is incorporated by reference herein.

Interposition of an absorptive ophthalmic element in the form of anintraocular, contact, or spectacle lens reduces the illuminanceaccording to the formula:L=K _(m) ∫T _(γ) T _(e,γ,L,) V _(γ) dγ photopicL′=K′ _(m) ∫T _(γ) L _(e,γ,L,) V′ _(γ) dγ scotopic  (0.3)where T_(γ) is the wavelength-dependent transmission of the opticalelement. Values for the integrals in equation 0.3 normalized to theunfiltered illuminance values computed from equation 0.2 for each of theprior-art blue blocking lenses are shown in Table I.

TABLE I Photopic Scotopic Reference FIG. Ratio Ratio Unfiltered 1.0001.000 Pratt ′430 0.280 0.164 Mainster 2005/0243272 0.850 0.775 PresentSystem 35 0.996 0.968 Present System 36 (solid line) 0.993 0.947 PresentSystem 37 0.978 0.951

Referring to Table I, the ophthalmic filter according to Pratt reducesscotopic sensitivity by 83.6% of its unfiltered value, an attenuationthat will both degrade night vision and stimulate pupil dilationaccording to equation 1.1. The device described by Mainster reducesscotopic flux by 22.5%, which is less severe than the Pratt device butstill significant.

In contrast, a film according to the present invention partiallyattenuates violet and blue light using absorptive or reflectiveophthalmic elements while reducing the scotopic illuminance by no morethan 15% of its unfiltered value. Surprisingly, systems according to thepresent invention were found to selectively inhibit a desired region ofblue light, while having little to no effect on photopic and scotopicvision.

In an embodiment, perylene (C20H12, CAS #198-55-0) is incorporated intoan ophthalmic device at a concentration and thickness sufficient toabsorb about two thirds of the light at its absorption maximum of 437nm. The transmission spectrum of this device is shown in FIG. 35 . Thechange in illuminance that results from this filter is only about 3.2%for scotopic viewing conditions and about 0.4% under photopic viewingconditions, as displayed in Table I. Increasing the concentration orthickness of perylene in the device decreases the transmission at eachwavelength according to Beer's law. FIG. 36 shows the transmissionspectrum of a device with a perylene concentration 2.27 times higherthan that for FIG. 6 . Although this device selectively blocks more ofthe phototoxic blue light than the device in FIG. 6 , it reducesscotopic illuminance by less than 6% and photopic illuminance by lessthan 0.7%. Note that reflection has been removed from the spectra inFIGS. 35 and 36 to show only the effect of absorption by the dye.

Dyes other than perylene may have strong absorption in blue or roughlyblue wavelength ranges and little or no absorbance in other regions ofthe visible spectrum. Examples of such dyes, illustrated in FIG. 46 ,include porphyrin, coumarin, and acridine based molecules which may beused singly or in combination to give transmission that is reduced, butnot eliminated, at 400 nm-460 nm. The methods and systems describedherein therefore may use similar dyes based on other molecularstructures at concentrations that mimic the transmission spectra ofperylene, porphyrin, coumarin, and acridine.

The insertion of dye into the optical path according to embodiments ofthe present invention may be accomplished by diverse methods familiar tothose practiced in the art of optical manufacturing. The dye or dyes maybe incorporated directly into the substrate, added to a polymericcoating, imbibed into the lens, incorporated in a laminated structurethat includes a dye-impregnated layer, or as a composite material withdye-impregnated microparticles.

According to another embodiment of the invention a dielectric coatingthat is partially reflective in the violet and blue spectral regions andantireflective at longer wavelengths may be applied. Methods fordesigning appropriate dielectric optical filters are summarized intextbooks such as Angus McLeod, Thin Film Optical Filters (McGraw-Hill:NY) 1989. An exemplary transmission spectrum for a six-layer stack ofSiO₂ and ZrO₂ according to the present invention is shown in FIG. 37 .Referring again to Table I, it is seen that this optical filter blocksphototoxic blue and violet light while reducing scotopic illuminance byless than 5% and photopic illuminance by less than 3%.

Although many conventional blue blocking technologies attempt to inhibitas much blue light as possible, current research suggests that in manyapplications it may be desirable to inhibit a relatively small amount ofblue light. For example, to prevent undesirable effects on scotopicvision, it may be desirable for an ophthalmic system according to theinvention to inhibit only about 30% of blue (i.e., 380-500 nm)wavelength light, or more preferably only about 20% of blue light, morepreferably about 10%, and more preferably about 5%. It is believed thatcell death may be reduced by inhibiting as little as 5% of blue light,while this degree of blue light reduction has little or no effect onscotopic vision and/or circadian behavior of those using the system.

As used herein, a film according to the invention that selectivelyinhibits blue light is described as inhibiting an amount of lightmeasured relative to the base system incorporating the film. Forexample, an ophthalmic system may use a polycarbonate or other similarbase for a lens. Materials typically used for such a base may inhibit avarious amount of light at visible wavelengths. If a blue-blocking filmaccording to the present invention is added to the system, it mayselectively inhibit 5%, 10%, 20%, 30%, 40%, and/or 50% of all bluewavelengths, as measured relative to the amount of light that would betransmitted at the same wavelength(s) in the absence of the film.

The methods and devices disclosed herein may minimize, and preferablyeliminate, the shift in color perception that results fromblue-blocking. The color perceived by the human visual system resultsfrom neural processing of light signals that fall on retinal pigmentswith different spectral response characteristics. To describe colorperception mathematically, a color space is constructed by integratingthe product of three wavelength-dependent color matching functions withthe spectral irradiance. The result is three numbers that characterizethe perceived color. A uniform (L*, a*, b*) color space, which has beenestablished by the Commission Internationale de L'eclairage (CIE), maybe used to characterize perceived colors, although similar calculationsbased on alternative color standards are familiar to those practiced inthe art of color science and may also be used. The (L*, a*, b*) colorspace defines brightness on the L* axis and color within the planedefined by the a* and b* axes. A uniform color space such as thatdefined by this CIE standard may be preferred for computational andcomparative applications, since the Cartesian distances of the space areproportional to the magnitude of perceived color difference between twoobjects. The use of uniform color spaces generally is recognized in theart, such as described in Wyszecki and Stiles, Color Science: Conceptsand Methods, Quantitative Data and Formulae (Wiley: New York) 1982.

An optical design according to the methods and systems described hereinmay use a palette of spectra that describe the visual environment. Anon-limiting example of this is the Munsell matte color palette, whichis comprised of 1,269 color tiles that have been established bypsychophysical experiments to be just noticeably different from eachother. The spectral irradiance of these tiles is measured under standardillumination conditions. The array of color coordinates corresponding toeach of these tiles illuminated by a D65 daylight illuminant in (L*, a*,b*) color space is the reference for color distortion and is shown inFIG. 38 . The spectral irradiance of the color tiles is then modulatedby a blue-blocking filter and a new set of color coordinates iscomputed. Each tile has a perceived color that is shifted by an amountcorresponding to the geometric displacement of the (L*, a*, b*)coordinates. This calculation has been applied to the blue-blockingfilter of Pratt, where the average color distortion is 41 justnoticeable difference (JND) units in (L*, a*, b*) space. The minimumdistortion caused by the Pratt filter is 19 JNDs, the maximum is 66, andthe standard deviation is 7 JNDs. A histogram of the color shifts forall 1,269 color tiles is shown in FIG. 39A (top).

Referring now to FIG. 39B, the color shift induced by the Mainsterblue-blocking filter has a minimum value of 6, an average of 19, amaximum of 34, and a standard deviation of 6 JNDs.

Embodiments of the present invention using perylene dye at twoconcentrations or the reflective filter described above may havesubstantially smaller color shifts than conventional devices whethermeasured as an average, minimum, or maximum distortion, as illustratedin Table II. FIG. 40 shows a histogram of color shifts for aperylene-dyed substrate according to the present invention whosetransmission spectrum is shown in FIG. 35 . Notably, the shift acrossall color tiles was observed to be substantially lower and narrower thanthose for conventional devices described by Mainster, Pratt, and thelike. For example, simulation results showed (L*, a*, b*) shifts as lowas 12 and 20 JNDs for films according to the present invention, withaverage shifts across all tiles as low as 7-12 JNDs.

TABLE II Avg. δ Min. δ Max. δ Std. (L*, (L*, (L*, Deviation δ ReferenceFigure a*, b*) a*, b*) a*, b*) (L*, a*, b*) Pratt 41 19 66 12 Mainster19 6 34 6 Present 35 7 2 12 2 System Present 36 12 4 20 3 System Present37 7 2 12 2 System

In an embodiment, a combination of reflective and absorptive elementsmay filter harmful blue photons while maintaining relatively highluminous transmission. This may allow a system according to theinvention to avoid or reduce pupil dilation, preserve or prevent damageto night vision, and reduce color distortion. An example of thisapproach combines the dielectric stacks shown in FIG. 37 with theperylene dye of FIG. 35 , resulting in the transmission spectrum shownin FIG. 41 . The device was observed to have a photopic transmission of97.5%, scotopic transmission of 93.2%, and an average color shift of 11JNDs. The histogram summarizing color distortion of this device for theMunsell tiles in daylight is shown in FIG. 42 .

In another embodiment, an ophthalmic filter is external to the eye, forexample a spectacle lens, goggle, visor, or the like. When a traditionalfilter is used, the color of the wearer's face when viewed by anexternal observer may be tinted by the lens, i.e., the facial colorationor skin tone typically is shifted by a blue-blocking lens when viewed byanother person. This yellow discoloration that accompanies blue lightabsorption is often not cosmetically desirable. The procedure forminimizing this color shift is identical to that described above for theMunsell tiles, with the reflectance of the wearer's skin beingsubstituted for those of the Munsell color tiles. The color of skin is afunction of pigmentation, blood flow, and the illumination conditions. Arepresentative series of skin reflectance spectra from subjects ofdifferent races is shown in FIGS. 43A-B. An exemplary skin reflectancespectrum for a Caucasian subject is shown in FIG. 44 . The (L*, a*, b*)color coordinates of this skin in daylight (D65) illumination are (67.1,18.9, 13.7). Interposition of the Pratt blue-blocking filter changesthese color coordinates to (38.9, 17.2, 44.0), a shift of 69 JND units.The Mainster blue-blocking filter shifts the color coordinates by 17 JNDunits to (62.9,13.1,29.3). By contrast, a perylene filter as describedherein causes a color shift of only 6 JNDs, or one third that of theMainster filter. A summary of the cosmetic color shift of an exemplaryCaucasian skin under daylight illumination using various blue-blockingfilters is shown in Table III. The data shown in Table I refer arenormalized to remove any effect caused by a base material.

TABLE III Reference FIG. L* a* b* δ (L*, a*, b*) Skin 14-15 67 19 14 0Pratt 39 17 44 69 Mainster 63 13 29 17 Present System 35 67 17 19 6Present System 36 67 15 23 10 Present System 37 67 17 19 6

In an embodiment, an illuminant may be filtered to reduce but noteliminate the flux of blue light to the retina. This may be accomplishedwith absorptive or reflective elements between the field of view and thesource of illumination using the principles described herein. Forexample, an architectural window may be covered with a film thatcontains perylene so that the transmission spectrum of the windowmatches that shown in FIG. 35 . Such a filter typically would not inducepupil dilation when compared to an uncoated window, nor would it causeappreciable color shifts when external daylight passes through it. Bluefilters according to the present invention may be used on artificialilluminants such as fluorescent, incandescent, arc, flash, and diodelamps, displays, and the like.

Various materials may be used in making films according to theinvention. Two such exemplary materials are Poly Vinyl Alcohol (PVA) andPoly Vinyl Butyral (PVB). In the case of PVA film it may be prepared bypartial or complete hydrolysis of polyvinyl acetate to remove theacetate groups. PVA film may be desirable due to beneficial filmforming, emulsifying, and adhesive properties. In addition, PVA film hashigh tensile strength, flexibility, high temperature stability, andprovides an excellent oxygen barrier.

PVB film may be prepared from a reaction of polyvinyl alcohol inbutanal. PVB may be suitable for applications that require highstrength, optical clarity, flexibility and toughness. PVB also hasexcellent film forming and adhesive properties.

PVA, PVB, and other suitable films may be extruded, cast from asolution, spin coated and then cured, or dip coated and then cured.Other manufacturing methods known in the art also may be used. There areseveral ways of integrating the dyes needed to create the desiredspectral profile of the film. Exemplary dye-integration methods includevapor deposition, chemically cross linked within the film, dissolvedwithin small polymer micro-spheres and then integrated within the film.Suitable dyes are commercially available from companies includingKeystone, BPI & Phantom.

Most dyeing of spectacle lenses is done after the lens has been shippedfrom the manufacturer. Therefore, it may be desirable to incorporate ablue-absorbing dye during the manufacture of the lens itself. To do so,the filtering and color balancing dyes may be incorporated into a hardcoating and/or an associated primer coating which promotes adhesion ofthe hard coating to the lens material. For example, a primer coat andassociated hard coat are often added to the top of a spectacle lens orother ophthalmic system at the end of the manufacturing process toprovide additional durability and scratch resistance for the finalproduct. The hard coat typically is an outer-most layer of the system,and may be placed on the front, back, or both the front and backsurfaces of the system.

FIG. 47 shows an exemplary system having a hard coating 4703 and itsassociated adhesion-promoting primer coat 4702. Exemplary hard coatingsand adhesion promoting primer coating are available from manufacturerssuch as Tokuyama, UltraOptics, SDC, PPG, and LTI.

In systems according to the invention, both a blue blocking dye and acolor balancing dye may be included in the primer coating 1802. Both theblue blocking and color balancing dyes also may be included in the hardcoating 1803. The dyes need not be included in the same coating layer.For example, a blue blocking dye may be included in the hard coating1803, and a color balancing dye included in the primer coating 1802. Thecolor balancing dye may be included in the hard coating 1803 and theblue blocking dye in the primer coating 1802.

Primer and hard coats according to the invention may be deposited usingmethods known in the art, including spin-coating, dip-coating,spray-coating, evaporation, sputtering, and chemical vapor deposition.The blue blocking and/or color balancing dyes to be included in eachlayer may be deposited at the same time as the layer, such as where adye is dissolved in a liquid coating material and the resulting mixtureapplied to the system. The dyes also may be deposited in a separateprocess or sub-process, such as where a dye is sprayed onto a surfacebefore the coat is cured or dried or applied.

A hard coat and/or primer coat may perform functions and achievebenefits described herein with respect to a film. Specifically, the coator coats may selectively inhibit blue light, while maintaining desirablephotopic vision, scotopic vision, circadian rhythms, and phototoxicitylevels. Hard coats and/or primer coats as described herein also may beused in an ophthalmic system incorporating a film as described herein,in any and various combinations. As a specific example, an ophthalmicsystem may include a film that selectively inhibits blue light and ahard coat that provides color correction.

The selective filter of the present invention can also provide increasedcontrast sensitivity. Such a system functions to selectively filterharmful invisible and visible light while having minimal effect onphotopic vision, scotopic vision, color vision, and/or circadian rhythmswhile maintaining acceptable or even improved contrast sensitivity. Theinvention can be formulated such that in certain embodiments the endresidual color of the device to which the selective filter is applied ismostly colorless, and in other embodiments where a mostly clear residualcolor is not required the residual color can be yellowish. Preferably,the yellowness of the selective filter is unobjectionable to thesubjective individual wearer. Yellowness can be measured quantitativelyusing a yellowness index such as ASTM E313-05. Preferably, the selectivefilter has a yellowness index that is no more than 50, 40, 35, 30, 25,23, 20, 15, 10, 9, 7, or 5.

The invention could include selective light wavelength filteringembodiments such as: windows, automotive windshields, light bulbs, flashbulbs, fluorescent lighting, LED lighting, television, computermonitors, etc. Any light that impacts the retina can be selectivelyfiltered by the invention. The invention can be enabled, by way ofexample only, a film comprising a selective filtering dye or pigment, adye or pigment component added after a substrate is fabricated, a dyecomponent that is integral with the fabrication or formulation of thesubstrate material, synthetic or non-synthetic pigment such as melanin,lutein, or zeaxanthin, selective filtering dye or pigment provided as avisibility tint (having one or more colors) as in a contact lens,selective filtering dye or pigment provided in an ophthalmic scratchresistant coating (hard coat), selective filtering dye or pigmentprovided in an ophthalmic anti-reflective coat, selective light wavelength filtering dye or pigment provided in a hydrophobic coating, aninterference filter, selective light wavelength filter, selective lightwavelength filtering dye or pigment provided in a photochromic lens, orselective light wavelength filtering dye or pigment provided in a matrixof a light bulb or tube. It should be pointed out that the inventioncontemplates the selective light wavelength filter selectively filteringout one specific range of wavelengths, or multiple specific ranges ofwavelengths, but never filtering out wavelengths evenly across thevisible spectrum.

Those skilled in the art will know readily how to provide the selectivelight wavelength filter to the substrate material. By way of exampleonly, the selective filter can be: imbibed, injected, impregnated, addedto the raw materials of the substrate, added to the resin prior topolymerization, layered within in the optical lens by way of a filmcomprising the selective filter dye or pigments.

The invention may utilize a proper concentration of a dye and or pigmentsuch as, by way of example only, perylene, porphrin or theirderivatives. Refer to FIG. 48 to observe varying concentration ofperylene and the functional ability to block wavelengths of light ataround 430 nm. The transmission level can be controlled by dyeconcentration. Other dye chemistries allow adjustment of the absorptionpeak positions.

Perylene with appropriate concentration levels provides balance inphotopic, scotopic, circadian, and phototoxicity ratios whilemaintaining a mostly colorless appearance:

TABLE V Photopic Scotopic Photo- Circadian Ratio Ratio toxicity RatioV_(λ) V′_(λ) Ratio (B_(λ)) (M′_(λ)) Reference (%) (%) (%) (%) Unfiltered100 100 100 100 Polycarbonate-undyed 88 87 86 74 Pratt 28 16 4 7Mainster 86 78 39 46 Mainster (−20 nm shift) 86 83 63 56 Mainster (+20nm shift) 84 68 15 32 HPOO dye (2x) 88 81 50 62 HPOO dye (x) 88 84 64 63HPOO (x/2) 87 84 72 66 HPOO (x/4) 89 87 79 71

Increases in contrast sensitivity are observed with appropriateconcentration of perylene. See Example 2, Table VI. It should be pointedout that the family of perylene based dyes or pigments are used, by wayof example only, for enabling the invention. When such a dye is used,depending upon the embodiment or application, the dye may be formulatedsuch that it is bonded molecularly or chemically to the substrate or acoating that is applied to the substrate such that the dye does notleach out. By way of example only, applications of this would be for usewith contact lenses, IOLs, corneal in-lays, corneal on-lays, etc.

Selective filters can be combined to hinder other target wavelengths asscience discovers other visible light wavelength hazards.

In one embodiment of the invention, a contact lens is comprised of aperylene dye formulated such that it will not leach out of the contactlens material. The dye is further formulated such that it provides atint having a yellow cast. This yellow cast allows for the contact lensto have what is known as a handling tint for the wearer. The perylenedye or pigment further provides the selective filtering as shown by FIG.48 . This filtering provides retinal protection and enhanced contrastsensitivity without compromising in any meaningful way one's photopicvision, scotopic vision, color vision, or circadian rhythms.

In the case of the inventive embodiment of a contact lens the dye orpigment can be imparted into the contact lens by way of example only, byimbibing, so that it is located within a central 10 mm diameter or lesscircle of the contact lens, preferably within 6-8 mm diameter of thecenter of the contact lens coinciding with the pupil of the wearer. Inthis embodiment the dye or pigment concentration which providesselective light wavelength filtering is increased to a level thatprovides the wearer with an increase in contrast sensitivity (as opposeto without wearing the contact lens) and without compromising in anymeaningful way (one or more, or all of) the wearer's photopic vision,scotopic vision, color vision, or circadian rhythms.

Preferably, an increase in contrast sensitivity is demonstrated by anincrease in the user's Functional Acuity Contrast Test (FACT) score ofat least about 0.1, 0.25, 0.3, 0.5, 0.7, 1, 1.25, 1.4, or 1.5. Withrespect to the wearer's photopic vision, scotopic vision, color vision,and/or circadian rhythms, the ophthalmic system preferably maintains oneor all of these characteristics to within 15%, 10%, 5%, or 1% of thecharacteristic levels without the ophthalmic system.

In another inventive embodiment that utilizes a contact lens the dye orpigment is provided that causes a yellowish tint that it is located overthe central 5-7 mm diameter of the contact lens and wherein a secondcolor tint is added peripherally to that of the central tint. In thisembodiment the dye concentration which provides selective lightwavelength filtering is increased to a level that provides the wearervery good contrast sensitivity and once again without compromising inany meaningful way (one or more, or all of) the wearer's photopicvision, scotopic vision, color vision, or circadian rhythms.

In still another inventive embodiment that utilizes a contact lens thedye or pigment is provided such that it is located over the fulldiameter of the contact lens from approximately one edge to the otheredge. In this embodiment the dye concentration which provides selectivelight wavelength filtering is increased to a level that provides thewearer very good contrast sensitivity and once again withoutcompromising in any meaningful way (one or more, or all of) the wearer'sphotopic vision, scotopic vision, color vision, or circadian rhythms.

When various inventive embodiments are used in or on human or animaltissue the dye is formulated in such a way to chemically bond to theinlay substrate material thus ensuring it will not leach out in thesurrounding corneal tissue. Methods for providing a chemical hook thatallow for this bonding are well known within the chemical and polymerindustries.

In still another inventive embodiment an intraocular lens includes aselective light wavelength filter that has a yellowish tint, and thatfurther provides the wearer improved contrast sensitivity withoutcompromising in any meaningful way (one or more, or all of) the wearer'sphotopic vision, scotopic vision, color vision, or circadian rhythms.When the selective filter is utilized on or within an intra-ocular lensit is possible to increase the level of the dye or pigment beyond thatof a spectacle lens as the cosmetics of the intra-ocular lens areinvisible to someone looking at the wearer. This allows for the abilityto increase the concentration of the dye or pigment and provides evenhigher levels of improved contrast sensitivity without compromising inany meaningful way (one or more, or all of) the wearer's photopicvision, scotopic vision, color vision, or circadian rhythms.

In still another embodiment of the invention, a spectacle lens includesa selective light wave length filter comprising a dye having perylenewherein the dye's formulation provides a spectacle lens that has amostly colorless appearance. And furthermore that provides the wearerwith improved contrast sensitivity without compromising in anymeaningful way (one or more, or all of) the wearer's photopic vision,scotopic vision, color vision, or circadian rhythms. In this particularembodiment of the invention, the dye or pigment is imparted within afilm that is located within or on the surface of the spectacle lens.

EXAMPLES Example 1

A polycarbonate lens having an integral film with varying concentrationsof blue-blocking dye was fabricated and the transmission spectrum ofeach lens was measured as shown in FIG. 45 . Perylene concentrations of35, 15, 7.6, and 3.8 ppm (weight basis) at a lens thickness of 2.2 mmwere used. Various metrics calculated for each lens are shown in TableIV, with references corresponding to the reference numerals in FIG. 45 .Since the selective absorbance of light depends primarily on the productof the dye concentration and coating thickness according to Beer's law,it is believed that comparable results are achievable using a hard coatand/or primer coat in conjunction with or instead of a film.

TABLE IV Photopic Scotopic Photo- Circadian Ratio Ratio toxicity RatioV_(λ) V′_(λ) Ratio (B_(λ)) M′_(λ) Ref. (%) (%) (%) (%) Unfiltered 100100 100 100 Polycarbonate- 4510 87.5% 87.1% 74.2% 85.5% undyed 3.8 ppm(2.2 mm) 4520 88.6% 86.9% 71.0% 78.8% 7.6 ppm (2.2 mm) 4530 87.0% 84.1%65.9% 71.1% 15 ppm (2.2 mm) 4540 88.3% 83.8% 63.3% 63.5% 35 ppm (2.2 mm)4550 87.7% 80.9% 61.5% 50.2%

With the exception of the 35 ppm dyed lens, all the lenses described inTable IV and FIG. 45 include a UV dye typically used in ophthalmic lenssystems to inhibit UV wavelengths below 380 nm. The photopic ratiodescribes normal vision, and is calculated as the integral of the filtertransmission spectrum and V_(λ) (photopic visual sensitivity) divided bythe integral of unfiltered light and this same sensitivity curve. Thescotopic ratio describes vision in dim lighting conditions, and iscalculated as the integral of the filter transmission spectrum and Vλ(scotopic visual sensitivity) divided by the integral of unfilteredlight and this same sensitivity curve. The circadian ratio describes theeffect of light on circadian rhythms, and is calculated as the integralof the filter transmission spectrum and Mλ (melatonin suppressionsensitivity) divided by the integral of unfiltered light and this samesensitivity curve. The phototoxicity ratio describes damage to the eyecaused by exposure to high-energy light, and is calculated as theintegral of the filter transmission and the Bλ (phakic UV-bluephototoxicity) divided by the integral of unfiltered light and this samesensitivity curve. Response functions used to calculate these valuescorrespond to those disclosed in Mainster and Sparrow, “How Much BlueLight Should an IOL Transmit?” Br. J. Ophthalmol., 2003, v. 87, pp.1523-29, Mainster, “Intraocular Lenses Should Block UV Radiation andViolet but not Blue Light,” Arch. Ophthal., v. 123, p. 550 (2005), andMainster, “Violet and Blue Light Blocking Intraocular Lenses:Photoprotection vs. Photoreception”, Br. J. Ophthalmol, 2006, v. 90, pp.784-92. For some applications, a different phototoxicity curve isappropriate but the methodology for calculation is the same. Forexample, for intraocular lens (IOL) applications, the aphakicphototoxicity curve should be used. Moreover, new phototoxicity curvesmay be applicable as the understanding of the phototoxic lightmechanisms improves.

As shown by the exemplary data described above, a system according tothe present invention may selectively inhibit blue light, specificallylight in the 400 nm-460 nm region, while still providing a photopicluminous transmission of at least about 85% and a phototoxicity rationof less than about 80%, more preferably less than about 70%, morepreferably less than about 60%, and more preferably less than about 50%.As previously described, a photopic luminous transmission of up to 95%or more also may be achievable using the techniques described herein.

The principles described herein may be applied to varied illuminants,filters, and skin tones, with the objective of filtering some portion ofphototoxic blue light while reducing pupil dilation, scotopicsensitivity, color distortion through the ophthalmic device, andcosmetic color of an external ophthalmic device from the perspective ofan observer that views the person wearing the device on their face.

Several embodiments of the invention are specifically illustrated and/ordescribed herein. However, it will be appreciated that modifications andvariations of the invention are covered by the above teachings andwithin the purview of the appended claims without departing from thespirit and intended scope of the invention. For examples, although themethods and systems described herein have been described using examplesof specific dyes, dielectric optical filters, skin tones, andilluminants, it will be understood that alternative dyes, filters, skincolors, and illuminants may be used.

Example 2

Nine patients were tested for contrast sensitivity using dyeconcentrations of 1× and 2× against a clear filter as a control. 7 ofthe 9 patients showed overall improved contrast sensitivity according tothe Functional Acuity Contrast Test (FACT). See Table VI.

Table VI is a contrast sensitivity test for dye samples with loadings ofX and 2X. Test was done in February 2007 at Vision Associates in Havrede Grace, Md. by Dr. Andy Ishak. The test consisted of 10 patients, eachtested with two filters, using the FACT contrast sensitivity testingprocess, with the following constraints. Seven of the 9 patients showedoverall improved contrast sensitivity results (columns 33-35). Patientsoverall showed improvement in both eyes on 18 of the 20 opportunities (2eyes×two filters×five FACT columns (rows 27-28). On average, patientsimproved by 2.3-3.4 for all 20 opportunities (row 25).

Having now fully set forth the preferred embodiment and certainmodifications of the concept underlying the present invention, variousother embodiments as well as certain variations and modifications of theembodiments herein shown and described will obviously occur to thoseskilled in the art upon becoming familiar with said underlying concept.It is to be understood, therefore, that the invention may be practicedotherwise than as specifically set forth herein.

What is claimed is:
 1. A display system comprising: a selective lighttransmission filter component of a film, a layer, or a coating having: atransmittance spectrum comprising: a first minimum value at a firstwavelength within a first wavelength range of 400-460 nm, a firstmaximum value at a second wavelength that is less than the firstwavelength, and a second maximum value at a third wavelength that isgreater than the first wavelength; and an average transmission of atleast 80% across a visible spectrum that includes the third wavelength.2. The display system of claim 1, wherein the display system is acomputer monitor.
 3. The display system of claim 1, wherein the displaysystem is a television.
 4. The display system of claim 1, wherein thefirst wavelength range is 430+/−20 nm.
 5. The display system of claim 1,wherein the first wavelength range is 430+/−10 nm.
 6. The display systemof claim 1, wherein the selective light transmission filter comprises atleast a dye and a pigment.
 7. The display system of claim 1, wherein theselective light transmission filter comprises one or more of: perylene,porphyrin, coumarin, acridine, and derivatives thereof.
 8. The displaysystem of claim 1, wherein the selective light transmission filtercomprises perylene or a derivative thereof.
 9. The display system ofclaim 1, wherein the selective light transmission filter comprisesporphyrin or a derivative thereof.
 10. The display system of claim 1,wherein the selective light transmission filter comprises a synthetic ora non-synthetic pigment.
 11. The display system of claim 1, wherein theselective light transmission filter comprises at least one of: melanin,lutein, and zeaxanthin.
 12. The display system of claim 1, wherein theselective light transmission filter comprises a yellowness index of nomore than
 10. 13. The display system of claim 1, wherein white light hasCIE (x,y) coordinates of (0.33+/−0.05, 0.33+/−0.05) when transmittedthrough the display system.
 14. A display system comprising: a lighttransmission filter component of a film, a layer, or a coating having: atransmittance spectrum comprising: a first minimum value at a firstwavelength within a blue light wavelength range that includes 430 nm, afirst maximum value at a second wavelength that is less than the firstwavelength, and a second maximum value at a third wavelength that isgreater than the first wavelength; and an average transmission of atleast 80% across a visible spectrum that includes the third wavelength.15. The display system of claim 14, wherein the display system is acomputer monitor.
 16. The display system of claim 14, wherein thedisplay system is a television.
 17. The display system of claim 14,wherein the light transmission filter comprises a yellowness index of nomore than
 10. 18. A system comprising: a computer monitor; and a lighttransmission filter configured to: block 5-50% of light transmission ateach wavelength within a wavelength range of 400-460 nm; and transmit atleast 80% of light across a wavelength range of 460-700 nm, and whereinthe light transmission filter is a component of a film, a layer, or acoating.
 19. The display system of claim 18, wherein the lighttransmission filter comprises a yellowness index of no more than 15.